Stereopticon.



No. 729,225. PATENTED MAY 26, 1903. J. A. SEAVBRNS. STEREOPTIGON.

APELIOA'IIOH FILED D110. 31. 1897.

0 MODEL; 8 SHEETS-SHEET1 a n2 Witnesses: P5 Inventor- O orneys.

Y NORRIS PETERS cc. lmcnolrmo. wmnmaron, o c.

PATENTED MAY 26, 1903-.

J. A. smvmms, STEREOPTIG ON.

APPLICATION FILED D30. 31, 1897.

8 SHEETS-SHEET 2.

nvenur A (SQ, ilms wz'nasses:

MJML 1; H m

oq'orneys.

PATENTED MAY 26, 1903.

J, A. SBAVBRNS.

STEREOPTIGON. APPLICATION 11.21) D30. 31. 1897.

a sung-sum 4.

H0 MODEL.

Wiinesses: 20

fivw v O 'orne ys.

PATENTED MAY 26, 1903.

No. 729,225. I

J. A. SEAVER'NS. STEREOPTIGON.

APPLICATION FILED mm. 31.1897.

30 MODEL.

m f .r,

lllllfllllllf I!!! V 1 z.

iii/Ill V 7 V V Witnesses.-

M, 2. W w.

Q K .oQ o'rneys.

ma Noams PETERS co, PHOTD-LIYHD,

PATENTED MAY 26, 1903.

J. A. SEAVERNS.

STEREOPTIGON.

APPLIUATION rum) p20. 31. 1,897.

8 SHEETS-SHEET 6..

B0 MODEL.

lhvenzfof: sq; ,rgz/W Witnesses PHOYc-LITNKL. WASHXNGTON. o c,

PATE'NTED MAY 26, 1903.

I. A. SEAVBRNS.

, STEREOPTIGON.

APPLICATION FILED no. 31. 1897-.

8 SHEETS-SHEET 7.

10 MODEL.

o. @Q m6\ m2 9 0 O O O mm. QQ N9 M W? o o o 0 Inventor: Q; 5

Witnesses.-

UNTTED STATES Patented May 26, 1903.

PATENT OFFICE.

JOHN A. SEAVERNS,.OF BOSTON, MASSACHUSETTS, ASSIGNOR OF THIRDS TO ALBERT T. THOMPSON, OF WEST NEWTON, MASSAOHU- SETTS.

sTi-ieeoeilcom.

SIECIFICATION forming part of Letters Patent NO. 729,225, dated. May 26, .1903. Application filed December 31. 1897. Serial No. 665,127. (No model.)

To all whom, it may concern:

Be it known that I,J OHN A. SEAVERNS, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Stereopticons, of which the following is a specificatiomreference being had therein to the accompanying drawings.

One general aim or object of the invention is to effect an improvement in the means of electrically lighting the lanterns which are employed for optical projection. Electric arclamps have been used heretofore in connection with optical lanterns, but they have not always proved satisfactory. Difficulties of various kinds have been encountered in their use, and a somewhat serious drawback is the fact that they have been of such a character and construction that where two or more lanterns have beenuscdin conjunction in a stereopticon it has been found impracticable and disadvantageous to locate one of the said lanterns vertically above the other, so that it has been found necessary to locate one lantern at one side of the other, on either the same level or, usually, on a higher level. This offsetting of one lantern to one side relatively to the other has been necessitated by the fact that in the forms of arc-lamps which have been used hitherto in connection with optical lanterns the carbons and the parts by which they are supported and fed take up a great deal of space vertically, so that if one lantern were placed vertically over the other it would have to be located at a height abovethe latter which would be so great as to be disadvantageous for a number of practical reasons.

Specifically stated, I have aimed to produce an optical lantern having an improved construction and arrangement of lighting devices which shall be simple, inexpensive, serviceable, and more compact and convenient in character and arrangement than the lighting devices which have been provided heretofore. In addition I have undertaken to obviate the disadvantage which I have just explained with respect to the employment of a plurality of lanterns in one apparatus-that is to say, I have in particular sought to enable one lantern advantageously to be placed vertically above the other and in close proximity thereto.

The first part of my present invention, therefore, has reference to provisions for elec-' trically lighting an optical lantern by means of an arc-lamp and for adapting the arc-lamp to the requirements of the lantern under the varying conditions of use, 85c.

Other aims or objects of the invention are to improve the general construction and worlv ing of optical lanterns.

Specifically stated, I have aimed to provide in improved manner for the support of the parts of the condenser-lens and for the ready application and removal of the said parts, for the ventilation of the said lens, for rendering the slide-carrier self-centering with reference to the condenser-lens, for permitting the slidecarrier readily to be connected with the condenser-support, and to be disconnected therefrom in order to give access to the said lens to enable it to be cleaned, and also to enable an optical stage to be produced to admit of the introduction of microscopic or chemical sub jects intermediate the condenser and the objective, &c.

The invention, therefore, has reference to a variety of features of general construction which are designed to improve the character and working of a lantern.

The invention will be described first with reference to the accompanying drawings, in which latter I have illustrated the best embodiments thereof which I have yet contrived, after which the distinguishing characteristics of the invention will be particularly pointed out and distinctly defined in the claims at the close of this specification.

Figure 1, Sheet 1, of the said drawings is a View in side elevation of a double-tier stereopticon embodying my invention. Fig. 2, Sheet 2, is a similar view of one of the arclamps removed from the stereopticon. Fig. 3, Sheet 3, is a view thereof in plan. Fig. 4, Sheet 4, is a view in end elevation from the left-hand side in Figs. 1, 2, and 3. Fig. 5,

Sheet .5, is a view in vertical section on the plane which is indicated by the dotted line 5 5 in Fig. 6, Sheet 6. Fig. (5, Sheet 6, isaview are received the tubes 10 10.

in elevation from the right in Figs. 1, 2, 3, showing the forward end of a lamp-hood and the carbons therein. Fig. '7, Sheet 7, is a view in vertical section on the dotted line 7 7, Fig. 1, looking in the direction which is indicated by the arrows at the ends of such line. Fig. 8 is a view in side elevation of the rear simple lens of the condenser and its holder or mount. Fig. 9, Sheet 7, is a view in vertical section on the dotted line 9 9 of Fig. 10, Sheet 8. Fig. 10 is a view in vertical section on the dotted line 10 10 of Fig. 1 looking in the direction which is indicated by the arrows at the ends of such line. Fig. 11, Sheet 8, is a View in vertical section on the dotted line 11 11 of Fig. 1 looking in the direction which is indicated by the arrows at the ends of such line. Fig. 12, Sheet 6, is :a view partly in vertical section on the line 12 12 of- Fig. 10, Sheet 8, looking in the direction which is indicated by the arrows at the ends of such line. Fig. 13 is a View in transverse section on the line 13 13 of Fig. 12.

Certain features of the present invention having been designed more especially with reference to their use in connection with stereopticons embodying a plurality of lanterns, I have shown in Fig. 1 of the accompanying drawings'a double-tier stereopticon. It will be obvious, however, that features of the invention hereinafter presented are in general capable of being utilized to equal advantage in stereopticons embodying more than two lanterns or in a single lantern that is used alone. Hence I do not limit myself in all respects to the employment of the invention in apparatus embodying a plurality of lanterns or in apparatus embodying any particular number of lanterns.

1 1 designate the supports to which in practice are applied the objectives (not shown) of the two lanterns. 2 2 designate the respective bellows, which extend rearwardly (toward the left in Fig. 1 of the drawings) from the said objective-supports 1 1. 3 3 are the respective slide-carriers which are connected with the rear ends of the said bellows 2 2, and 4 4 are the supports for the condensers.

The respective lamps pertaining to the two lanterns are designated 5 5, collectively, the positive carbon of each lamp being designated 6 and the negative carbon being designated 7, while the lamp-hood which is employed in connection with the forward end of each lamp is designated 8, a second or so-called lanternhood 81 being employed in connection with such end also. To the opposite sides of each objective-support 1 are secured two rearwardly-extending rodsf) 9, Fig. 1, Sheet 1; Fig. 7, Sheet 7; Figs. 10 and 11, Sheet 8, and Figs. 12 and 13, Sheet 6. Upon these latter The said tubes 10 10 are free to slide lengthwise upon the rods 9 9, and they are provided at their forward ends with clamping-screws 11 11, by

means of which to secure them in position upon the said rods. Upon the tubes 10 10 of each obj ective-support 1 are mounted the condenser-support 4, the lamp 5, and the lanternhood 81 pertaining to the corresponding lantern. Each condenser-support 4 is provided with bearings 12 12 to receive the corresponding tubes 10 10, while each lamp is furnished with a supporting cross-piece or slide 13, (see particularly Fig. 4, Sheet 4,) the opposite ends of which last are provided with eyes 14 14 to fit upon the rear portions of the said tubes. The opposite sides of the lantern-hood 81 pertaining to each lamp are equipped with ears 15, having eyes 16 16, Fig. 1, fitting upon the intermediate portions of the'length of the tubes 10 10. Reference has been made alreadyto the fact that the tubes 10 10 are adjustable lengthwise upon the rods 9 E) and are provided whit the screws 11 11, by means of which to secure them in the desiredposition of adjustment upon the said rods. This adjustment of the said tubes effects a joint adjustment of the condenser, lamp, and lantern-hood of each lantern relative to the objective of the latter. The condenser-support 4, lamp, and lanternhood pertaining to each lantern also are adjustable individually or severally upon the pair of tubes 10 10 of such lantern. For the purpose of securing stability of the condensersupport its bearings 12 12 are made of considerable length, as shown clearly in Fig. 1, Sheet 1, and Fig. 12, Sheet 6. The said bearings may in practice be made integral with the support 4; but by preference I form them of separate tubular pieces which are fitted at their rear ends into holes that are bored through the support 4 for their reception. Each bearing 12 is formed with a shoulder at 121 to fit against the adjacent forward face of the condenser-support 4, (see Fig. 12, Sheet 6,) and the extreme rear end of the bearing after being passed through thehole in the condenser-support 4 is expanded to form a flaring lip 122, taking against the rear side of condenser-support 4. This affords a convenient means of holding the bearings 12 12 in the condenser-support 4 and enables me to dis pense with the use of other holding devices such, for instance, as solder or screw-threads. The shoulder 121 and lip 122 of each bearing 12 hold the said bearing from longitudinal movement in consequence of their engagement with the opposite sides of the condensersupport 4, and the bearing thereby is held fixedly in place in the said condenser-support. I provide each bearing 12 with a device by means of which to lock or clamp the same and the corresponding tube 10 together at the required place in the length of the said tube 10. In some cases a simple clamping-screw may be employed, such screw making contact by its tip with the surface of the tube 10. Preferably, in order to guard against injury to the tube resulting from the action of the said screw, I employ in connection with each bearing 12 clamping devices consisting of a split ring 123, which is fitted within an annular recess 12% at one end of the bearing, the said split ring being prevented from rotating within the bearing by means of the pin 125, which projects into the opening between the ends of the ring,and a clamping-screw 126, which is' fitted to a hole that is tapped in the bearing, the said clamping-screw serving to enable the ring to be forced against the surface of the tube 10. The split ring serves as a shoe intervening between the end of the clamping-screw and the surface of the tube 10. By means of the split ring 123 and screw 126 the bearing 12 may be clamped upon the exterior of the tube 10, wherever desired, in the direction of the length of said tube and without danger of inj uryto the tube. The slide 13 of each lamp is held at the required place on the pair of tubes 10pertainin g to suchlamp by means of one or more clamping-screws 141, (see more particularly Fig. 3, Sheet 3, and Fig. 1, Sheet 4,) provided in connection with one or more of the eyes 14, the threaded stem of the screw being applied to a tapped hole in the eye and the inner end of the screw engaging with the surface of the tube 10, passing The lantern-hood S1 of through such eye. each lamp is left free for convenience in being moved or adjusted by hand upon the pair of tubes 10 1O pertaining to such lamp. In a stereopticon embodying a plurality of lanterns the preferred arrangement of the latter is one vertically above the other. In Fig. 1 of the drawings I have represented the two lanterns as thus arranged. The lower objectivesupport 1 and lower condenser-support 4 are intended to rest upon the table or other base to which the stereopticon is applied. The upper objective-support 1 is by preference connected pivotally with the lower obj ectivesupport 1, as at 17, Fig. 1. The upper condenser-support -l is supported from the lower condenser-support, set-screws 18 being interposed, as in Fig. 1, in order to enable the upper lantern to be adjusted vertically for the purpose of causing the views thrown by the two lanterns to register with each otherthat is to say, to come into exact superposition upon the screen.

In order to enable me to arrange the lanterns to advantage, one vertically above the other, as in Fig. 1, while utilizing arc-lamps, I dispose the carbons of each lamp at an angle to each other one of such carbons, herein the positive, being located in the line of the optical axis of the lantern and extending len gthwise of the said axis, while the other carbon, herein the negative, meets the carbon first mentioned at an angle, as just indicated. Herein the latter carbon is shown as extending upwardly from below the carbon first mentioned and with its upper extremity below the forward extremity of the horizontal carbon. Forsome reasons I prefer the rightangled arrangement of the carbons that is shown in the drawings. This arrangement of the carbons at an angle to each other and with one thereof extending lengthwise of the optical axis causes practically all of the light radiating from the are an d from the incandescent portions of the carbons to be thrown forward in the line of the optical axis and to be projected through the condenser. It is, moreover, particularly advantageous in the case of stereopticons, since it enables the supporting and feeding devices for one of the carbons (the horizontal one) to be arranged and disposed horizontally at the rear of the condenser and in the direction of the length of the lantern, inasmuch as the feed of such carbon is required to be along a horizontal line which is substantially in continuation of the optical axis of the lantern. With this arrangement of the supporting and feeding devices for the horizontal carbon all necessity is obviated for any extension or projection of the parts of the lamp of either lantern above the height of the main portions or body of the said lantern. The absence of upwardly-projecting portions of the lampthat is to say,portions projecting above the top of the main portions or body of the lantern-permits me to locate the upper lantern immediately above the lower lantern to advantage, for it enables the two lanterns to occupy positions in close proximity to each other. Heretofore in the case of the stereoptieons which I have met with in practice, in those which have been lighted by electric arclamps, the carbons have been held in a vertical or substantially vertical position, and the extension of the upper carbon of the arc-lamp pertaining to each lantern, and of the devices which are concerned in holding and feeding the said upper carbon upward above the op tical axis and the place of the arc, has increased the height of each of the lanterns at the lighting end thereof so much as to render it impracticable to place the upper lantern vertically above the lower lantern. It therefore has been customary to offset one lantern laterally with respect to the other, as stated hereinbefore.

The holders for the two carbons 6 and 7 of each lamp are designated 19 and 20, respec tively. The holder 19 has the stem thereof fitted to a hole that is provided for its reception in a block 21. (See more particularly Fig. 3, Sheet The said stem is held in the said hole by a clamping-screw 22. 21 is connected with a sliding block 23, Figs. 1. and 2, by means of a screw or screws 24 passing through a projection on the block 21 and into the block 23, the block 21 being insulated by means of suitable insulating material, as sheet-mica, intervening, as at 25 25, between the same and said screw or screws 24 and block 23. The block 23 slides along guide-rods 26 26, which extend horizontally between uprights 27 27, which last are secured at opposite ends of a plate 28, mounted on a table or platform 29, the upper ends of the said uprights being connected by means of a plate 30.

31 is a shaft which is j ournaled in hearings in the uprights 27 27 and is provided at its outer end with a wheel 32, by means of which The block cally with equal rapidity.

to rotate the same when it is required to be actuated. Power may be applied to this wheel 32 by hand or automatically, whichever may be deemed most desirable in practice. I11 the present instance I have contemplated that the said shaft 31 shall be operated by hand, and accordingly the said wheel 32 is herein represented as a hand-wheel. Intermediate the uprights 27 27 the shaft 31 is screwthreaded, and the threaded portion of the said shaft engages a corresponding internal thread that is provided in the block 23. Thus the rotation of the shaft 31 serves to move the said block and the attached parts, including the horizontal carbon 6,'in the direction of the length of the shaft 31.

33 is a block which is secured to the under side of the table or platform 29 near the forward end thereof, and 34 34 are side pieces which are secured to the said block 33 and support at their lower ends a similar block 35. To the said blocks 33 and 35 are applied guide-rods 36 36, on which is fitted to slide vertically the block 37, with which is connected the arm 38, the said arm being secured to the said block by means of a screw or screws 39, (see Fig. 4, Sheet 4,) the arm being insulated from the said screw or screws and the said blockby suitable insulating material, as sheet-mica, (indicated at 40.) The arm 38 is socketed to receive the stem 41 of the holder 20, the said stem being secured in place in the socket of the said arm by a clampingscrew 42. To bearings in said blocks 33 and 35 is fitted a vertical shaft 43, which latter is screw-threaded intermediate the said bearings to fit an internally-tln'eaded portion of the block 37. The shafts 31 and 43 are connected to turn in unison, as by gears 44 and 45. Hence when power is applied to the shaft 31 to rotate the same both shafts will be caused to rotate simultaneously to advance or retract the carbon-holders 19 and 20 in unison. In some places in which it is desired to use a lantern or stereopticon a direct cur 'rent is found to be available, while in others it is an alternating current which is available. The carbons do not burn away or consume in the same relative proportions in the case of both currents. When 'a direct current is used, the positive carbon is consumed at practically twice the speed with which the negative carbon is consumed, while with an alternating current the two carbons are consumed practi- I desire to enable the devices to be used with either current, as may be required. In order to permit this, it is necessary to provide means of compensating for the differences in the cases of the two currents in the relative rates of consumption of the two carbons. To this end I interpose change-gearingintermediate the shafts 31 and 43, in order to enable me to vary the relative rate of feed of the two carbons 6 and 7. Thus I form the wheel 45, which is a crown-gear, with two concentric circles of teeth, as indicated at 451 and 452 in Fig. 3 of the drawings,

carbon 6 extends.

and I spline the shaft 31, as shown in Figs. 2 and 3, so as to enable the said wheel 44 to be moved into engagement with either of the said circles of teeth, as may be desirable. The said gear 44 is secured in place on the shaft after adjustment by means of the clamping-screw 46. The outer circle of teeth 451 is substantially twice as great in diameter as is the wheel 44, and the latter is caused to engage therewith, as indicated in the drawings, when a direct current is being used. hen it is desired to use an alternating current, the wheel 44 is shifted into engagement with the inner circle of teeth 452.

Each of the carbon-holders 19 and 20 is provided with a follower 461, (see more particularly Figs. 3 and 4,) working in an opening 47, that is provided in the holder for the reception thereof. 48 48 are the thumb-screws, by means of which the said followers 461 461 are operated. The working face of each follower is composed of two inclined facets, as at 49 49 in Fig. 4, meeting at an angle, while the opposing portions of the holder are formed with similar facets O 50, also meeting at an angle. After a carbon has been placed in position in one of the holders by passing the carbon lengthwise through the opening in the said holder the operation of forcing the follower inwardly by rotating the screw 48 will cause the carbon to become seated in the opposite angular recesses of the holder and its follower, so as thereby to be securely held. The carbon contacts with the one side of body of the holder at two points or places which are disposed oppositely with reference to the follower and the follower bears against an opposite side of the carbon at a point or place longitudinally i11- termediate the contacts with the body of the holder. In consequence of the carbon being engaged at three alternating points or places when the thumb-screw is turned in, so as to press the follower into firm engagement with the carbon, the last is held in proper alinement with the axis of the feed-screw.

The lamp-hood 8 is mounted upon the forward end of the table or platform 29. It is substantially trumpetshapcd and is held to the said table or platform by screws 51. (See Fig 5, Sheet 5.) This lamp-hood is designed to prevent the radiation of light in undesired directions and is of great importance as a means of confining the sounds which are produced by the lamp. At the rear extremity of its contracted portion it is provided with a diaphragm 52, preferably of sheetmica, which is held in place across the opening of the said end by means of a clamping-ring 53, that is secured in place by means of screws 54 54. Through a central hole in this diaphragm the In the lower side of the ex panded portion of the lamp-hood is an openingwhich is crossed by a diaphragm55of sheetmica, the said diaphragm being held by a clamping-ring 56, which is secured in place by means of screws 57 57. Through a hole in the said diaphragm 55 the vertical carbon 7 ex- ILO tends.

conductive of both heat and electricity,so they not only are capable of insulating the carbons from their metallic surroundings in case of misplacement of the carbons, but they serve to cut oif certain portions of the radiated heat, while at the same time the openings through which the carbons pass, in consequence of being somewhat greater in diameter than the carbons themselves, permit currents of cool air to flow inwardly along the carbons, thus assisting in the ventilation and cooling of the lamp and adjacent parts. In the upper side of the lamp-hood, above the meeting place of the carbons, a hole 58 is provided for the escape of the heated air and gases. A rearwardly-extending deflector 59 is secured by screws 60 60 to the exterior of the lamp-hood 8 over the said hole. 811, Fig. 5, isa hole or window in one side of the lamp-hood adjacent the meeting ends of the carbons, 812, Fig. 4, being a cover of sheet-mica which is held in place by a ring 813, which is fastened on by screws 814. The enlarged forward end of the lamp-hood is closed save at the center by an incombustible curtain or diaphragm in the form of an annulus 61,which I heretofore have made of asbestos, which is held between the said end and a clamping-ring (32, the latter being fastened to the end of the lam p-hood by screws 63 63. This curtain or diaphragm cuts oil a large part of the heat which otherwise would pass toward the condenser and tend to injure the lens, while the central opening 64 allows the passage of the light-rays. In consequence of being soft and yielding it operates also to deaden the sounds which are produced within the lamp-hood.

\Vith the object in view of still further cutting off theheat that is radiated from the lamp, of deadening the sounds produced by the lamp, and of preventing the movement of heated currents of air or gases from around the lamp forward to the condenser, I dispose within the lantern-hood 81 a second curtain or screen in the form of an annulus of incombustible materialfor instance, of asbestos .the same being designated herein 65 and being attached by means of bolts or screws 66 to a support in the form of an annulus 67, of sheetmet-al, the last-mentioned part being riveted to L-shaped strips 68 G8, which in turn are riveted to the lantern-hood 81 and its support, as indicated in Fig. 5. Openings at 69 (it) in the top and bottom of the hood provide for the ventilation of the latter by permitting the heated air to escape freely at the top and cool air to enter freely below.

7 O is a fiat shield extending transversely above the upper opening 6 9, it being supported on upright portions 71, which are riveted to the cover and the shield, as shown.

The lantern-hood 81 substantially incloscs the lamp-hood 8 and the forward portion of the lamp and in practice is arranged to eX- tend forward to within a short distance of the rear side of the condenser-support 4, as indi- The diaphragms 52 and 55 are non-' i standard 7 2.

cated in Fig. 1. The table or platform 29 is mounted on the upper end of a screw-threaded This standard has fitted thereon the nut 7 3, the latter havinga wheel 74 to facilitate the adjustment thereof. The nut takes bearing at its lower end on the upper end of the thimble 75, through which latter the lower portion of the standard passes freely, the said thimble 75 having a flange 751 at its upper end, as shown,which flange rests on the upper end of the tubular boss 76, that is provided on the slide 13. In this manner the table or platform and the various parts which are mounted thereon are supported on the slide13, and the height of the said table or platform is varied by effecting a rotary adjustment of the nut 73 on the standard 72. Each lamp therebyis made vertically adjustable relative to the other parts of the lantern to which it pertains. Capacity is conferred upon the lamp for angular adjustment transversely or in a horizontal plane in order to enable the carbons and lamp-hood to be disposed in proper position with respect to the optical axis. The preferred mode of providing for this is shown in the drawings, in which latter I have represented the standard 7 2 as formed with a longitudinal groove 77 (see Fig. 4) to receive the inner end of the stem of the screw 78, the threaded portion of which stem is fitted to a threaded hole made through the thimble 75. By pressing the screw 7 8 laterally the parts may be rotated upon the vertical axis of the standard. To permit of the lateral movement of the screw, ahorizontally-extending slot 79 is made through the boss 76, and in effecting the angular adjustment to which reference has just been made the stem of the screw 78 moves around in the slot. The desired adjustments having been effected, the post or standard may be locked in place to prevent accidental or unintentional vertical movement of the same and the parts carried thereby by tightening up the screw 78 until the standard 7 2 has been clamped tightly within the thimble 75, and unintentional angular movement is prevented by tightening up the lockingscrew 781, the threaded stem of which fits a threaded hole in boss 76, while the inner end of said stem is caused to bear against the exterior surface of the thimble 7 5.

82 and 83 are binding-posts, the former being applied to a standard 84, which is mounted on the plate 30, while the binding-post 83 is applied to the table orplatform 29 and extends downwardly therefrom. Each of the said binding-posts is insulated by means of sheetmica 85 and is provided with a suitable binding-screw S6. A suitable insulated wire 87 extends from the binding-post 82 to the block 21 and is secured to the said post and block by the binding-screws 88 88. A metallic strip 89, extending along the upper surface of the table or platform 29, but insulated therefrom by sheet-mica 85, (see Figs. 3 and 4,) is in electrical communication at one end thereof with the binding-post S3 and at the other end the said case.

thereof with the binding-post 91. An insulated wire-92 extends from the said bindingpost 91 to the arm 38 of the slide 37, which supports the holder 20 of the vertical carbon 7, the opposite ends of the said wire being secured to the said binding-post and the said arm by binding-screwsv 93 93.

Precautions must be taken against injury to the condenser-lens resulting from the heat which is generated by the lamp. Reference has been made herein already to the screens 61 and of asbestos, which I provide for the purpose of preventing as much as possible of the heat from obtaining access to the condenser, and to the features of construction of the lamp-hood and lantern-hood which provide for the ventilation thereof. In addition I have taken especial pains to provide for the efficient ventilation of the condenser-cell and the component simple lenses of the condenser and have been careful to so construct the parts in which the said simple lenses are mounted as to provide for expansion and contraction as the said lenses become heated and cooled. I have also provided for supporting the parts of the compound condenser-lens in a convenient manner in a lantern and for the removal and replacement of the same readily and expeditiously whenever required for cleaning or other purposes. In these connections reference may be had more particularly to Fig. 1, Sheet 1, and Figs. 7, 8, and 9, Sheet 7.

94 designates the simple lens which constitutes the rear portion of the compound condenser-lens, and 95 designates the simple lens which constitutes the front portion of the condenser-lens. The mount for the simple lens 95 consists of a case 96, having an inturned flange 97 at its forward end and an outturned flange 98 at its rear end. The lens 95 fits within the said case with the edge portions of its plane face in contact with the said inturned flange 97, the lens being held pressed up against the said flange by the spiral spring 99, which latter is located within the case 96, as shown in Fig. 9, the forward convolution of the said spiral bearing against the convex face of the lens 95 near the periphery thereof. The lens 95 is somewhat less in diameter than the interior of the case 96, so that the said lens is free to move to a certain extent laterallywithin The spiral spring 99 operates through its contact with the convex face of the lens 95 to center the said lens automatically within the case 96. The looseness of the fit of the lens within the case and the'elasticity of the spring permit the simple lens 95 to expand freely when heated and obviate all tendency to occasion breakage thereof. The spring-retainer 99 is made movable with relation to the case 96, so as to enable it to be withdrawn for the purpose of introducing the simple lens 95 into place and afterward to be inserted at the back of the said lens. Preferably I make the spring into place and in withdrawing thesame. This insures the proper holding of the simple lens 95. I find it convenient to turn the rear end of the wire composing the spiral spring 99 radially outward, as at 100, and to pass the said outturned end through a hole 101. in the case 96, (see Fig. 9,) thereby securing against accidental dislodgment. In manipulating the spring it may be turned upon the said outturned end 100 as upon a pivot. The mount for the simple lens 94, constituting the rear portion of the condenser, consists of a fiat ring 102, with a number of bent arms 103 projecting from the rear side thereof, the said arms being shaped to fit and engage with the edge of the said simple lens 94, as is indicated most clearly in Fig.8. The condenser-support 4 is rabbeted on its opposite sides, as indicated in Fig. 9, leaving a thin annular web 104 around the central opening 105, through which the lightrays pass. The flange 98 of the front mount and the ring 102 of the rear mount fit against opposite faces of this web 104. For the purpose of securing the two mounts detachably in place against the said opposite faces of the web 104 I provide the condenser-support4 at opposite sides of the said web with inwardlyextending projections 106 106, as shown in Figs. 7 and 9, on the rear side of the condensersupport. Preferably I employa pair of these projections 106 106 on each side of the said web 104 and locate them diametrically opposite each other, as represented in Fig. 7. In the drawings I have shown only the securing means in connection with the rear 111 ount, but the application of the said means to the forward mount will be obvious. The projections on the one side of the web 104 are spaced sufficiently far from the said web to receive between them and the web the flange 98 of the front mount, while those on the other side of the said web are spaced therefrom sufficiently to receive between them and the web the ring 102 of the rear mount. The flange 98 and the ring 102 are each notched, as indicated at 107 in Fig. 7. In applying the mounts to the eonden ser-support, one edge of the flange 98 or of the ring 102 is slipped under one of the projections 106 at the proper side of the web 104, and then the mount, after having been turned around so as to bring the notch 107 into position to receive the remaining projection 106, is pressed up against the web 104, the said projection passing through the said notch, after which the mount is turned around its axis so as to shift the notch away from the projection, as indicated in Fig. 7, which looks the mount in place. The ring 102 rests on a pair of projections extending rearwardly from the web 104, on opposite sides of the middle of the lower portion thereof. These projections conveniently are constituted by the heads of screws 108, the stems of which enter the said web, and they form a convenient means of centering the rear mount. The body of the case 96 of the front mount extends through a central opening in a plate 1.09. The lower nected rigidly by short posts or pins 111 (see Fig. 1) with the rear plate 112 of the slideearrier Since the exterior of the case 96 closely fits the hole through the plate 109, this positive connection of the said plate with the slide-carrier secures perfect centering of the slide-carrier with relation to the condenser.

and maintains it in proper registerwith the latter. The plate 109 requires to be connected with the condenser-support a, in order that the slide-carrier may not accidentally get out of adjustment. In order to enable the said plate conveniently and expeditiously to be engaged with the condenser-support and also disconnected therefrom whenever required as, for exa1nple,when it is required to move the slidecarriertoward the objective-support, in order to produce in front of the condenser-lens a space great enough to constitute an optical stage for the reception of microscopic or chemical subjectsl have provided the condensen support with pairs of opposite projections 113 113, (see Fig. 10,) between which and the surface of the condenser-support the edges of the plate 109 may be slipped, and I have formed the said edges with notches 11% 114E of a suitable size to permit of the passage therethrongh of the said projections. In connecting the plate 109 with the condenser support the notches of the plate are presented to the proj ections, and on pressing the plate toward the condenser-support the projections pass through the notches, after which a slight downward movement of the plate carries the notches below the projections so as to lock the plate in place, this downward movement being arrested by the contact of the lower edge of the plate with the ledge or projection 110, to which reference has been. made. 111 11] are latches connected with the respective objective-supports 1 1 and engaging with pins 1&2 1&2 or the like on the slide-carriers 3 3, to hold the latter in their forward position when the production of the optical stage aforesaid is desired.

Holes 115 are made through the upper por tion of the case to permit of the escape of heated air from around the simple lens 95. \Vhen hood S1 is in its working position, a space, as 11 exists between the front end of the hood S1 and the rear side of the condensersupport for the purpose of permitting the unobstructed movement of currents of air. This opening extends entirely around the rearsimple lens 91, and, in conjunction with the skeleton form of the mount for the said lens 94, cfficiently provides for ventilation between the two simple lenses 94 and 95, since free escape of heated air from between them is enabled, while the entrance of a stream of cool air between the two is facilitated, thereby securing the greatest possible eificiency in keeping the parts of the condenser-lens cool and obviating injury to the same from the heat of the lamp. The rear simple lens 94 is supported at a sufficient distance at the rear of the plane of the rear surface of the web 10% of the condensersupport 4: to guard against any obstruction of the vertical movement of air in front of such simple lens.

117, Fig. 11, is the support on which the slides rest, 118 being the spring which bears against the upper edge of each slide and holds it down onto the said surface, and 1221 the spring which presses the slide rearwardly against the plate 112.

119 is the adj usting-screw, against the inner end of which the slides take bearing in order that the said slides maybe centered properly.

120 is an adjustable piece arranged to slide transversely of the lantern and having a se ries of notches 1211, each of which latter is adapted to receive the fixed projection 122, the latter being provided on the slide-carrier.- for the purpose of causing the said piece 120 to be held in the desired position of adjustment. The said piece 120 has the screw 119 fitted to a hole that is tapped in an upwardlyextending projectionor arm thereof, and is itself meant to be adjusted transversely of the lantern in order to accommodate various lengths of slides, the screw 119 serving to enable a finer degree of adjustment to be sccured.

The piece 120 may be shifted to suit slides of different lengths without alterin the position of the screw, while the latter is turned in bringing the vertical lines of the picture or subject on the slide into exact and precise position. The whole attachment may be re moved and reapplied whenever thisis desired without disturbance of the screw 119.

I do not herein lay claim to the features of construction of the lamp per 86, for I have made the same the subject of claim in a divisional application.

I claim as my invention- 1. The combination with the objective-support, and the rods 9, 9, secured to the objective-support, of the tubes 10, 10, fitted upon the rods 9, 9, movable lengthwise thereon and provided with means of securing them in the desired positions of adjustment thereon, the lamp, hood, and COlldGllSGT-SHPIJOl'lZ mounted on. the said tubes, the said hood having separate capacity for movement on the said tubes, and means of securin g the said lamp and condenser-support in the desired positions of adjustment on the said tubes, substantially as described.

2. The combination with the obj ective'support, and the rods 9, 9, secured to the objective-support, of the tubes 10, 10, fitted upon the rods 9, 9, movable lengthwise thereon, and provided with means of securing them in the desired posit-ion of adjustment thereon, the con denser-support provided with the bearings 12, 12, fitting the said tubes and movable thereon, the clamping-screws applied to the bearings 12, 12, and the rings intermediate the said screws and the said tubes, substantially as described.

3. The combination with the lower objective-support,the upper obj ective-support c011- nected pivotally with the said lower objective-support, and the pair of rods 9, 9, projecting rearwardly from each of the said objective-supports, of the tubes 10, 1.0, fitted upon the rods 9, 9, movable lengthwise thereon, and provided with means of securing them in the desired positions of adjustment thereon, the lamps and condenser-supports mounted on the respective pairs of the said tubes, the lantern-hood also mounted on said pairs of tubes and separately adjustable thereon, means of securing the respective lamps and condenser-supports in the desired position of adjustment on the respective pairs of tubes, and adjusting devices interposed between the upper and lower condenser-support, substantially as described.

l. The combination with the objective-s11 pport, the rod 9 projecting therefrom, and the condenser-support, of the bearing 12 seated in an opening in the said condenser-support and through which the said rod 9 passes, the said bearing having the shoulder at 121 in contact with one side of the said condensersnpport and its end expanded at the other side of the latter, whereby the said bearing is held in place, substantially as described.

5. In combination, a plurality of lanterns in a vertical series, and a plurality of electric-arc lamps, one for each lantern, and each lamp having its carbons disposed at or sub stantially at right angles with relation to each other, substantially as described.

6. The combination with the carbons arranged at an angle to each other, and the table supporting the said carbons, of the post on which the said table is mounted, means to adjust the said post vertically, and means to eftect an angular adjustment of the table and post around the axis of the latter, substantially as described.

7. The combination with the carbons arranged at an angle to each other, and the table supporting the said carbons, of the screw-threaded post on which the said table is mounted, the nut 73 which is applied to the said post to adjust the same vertically, the thimble supporting the said nut and connected to turn in unison with the post, the support for the said thimble, and means for effecting rotary adjustment of the said thimble in the said support, to give an angular adjustment to the said carbons, substantially as described.

8. The combination with the carbons arranged at an angle to each other, and the table supporting the said carbons, of the longitudhially-grooved screw-threaded post on which the said table is mounted, the nut '7 which is applied to the said post to adjust the same vertically, the thimble supporting the said nut, the support for the said thimble, the screw 78 applied to the said thimble and entering the groove of the post, and means of locking the thimble in the desired position of rotary adj ustment,substantially as described.

9. The combination with the con denser-lens and the lamp, of a souml-conlinin hood having an opening for the passage of the rays of light to the lens, and in conjunction with the opening one or more annular screens or curtains to obstruct and deaden sound-waves, substantially as described.

10. The combination with the carbons, and the condenser-lens in advance of the same, of an inclosing hood, and a screen located at the front end of the said hood to obstruct and deaden soundwaves and the passage of heat toward the lens, the said screen having the central opening for the passage of light-rays, substantially as described.

ll. The combination with the condensersupport and a simple lens constituting one mem berof the condenser-lens, of the skeleton mount or hold er having the arms thereof fitted to engage with the said simple lens, whereby to permit of free and unobstructed passage of air around and in front of the said simple lens, substantially as described.

12. The combination with the condensersupport and the simple lens which constitutes the rear portion of the condenser-lens, of the rear mount or holder consisting of the ring 102 adapted for attachment to the condensersupport and the separated rearwardly-projecting arms 103, 103, to engage with the said simple lens and hold the latter in space rearward of the condenser-support, whereby to permit of free and unobstructed passage of air around and also in front of the said simple lens,,between the same and said ring, substantially as described.

13. The combination with the condensersupport and a lens, of the mount or holder consisting of the case 96 to receive the lens and having a lens-retainer constituted by the spiral spring 99 fitted within the said case and engaging with the rim of the lens, the said spring holding the lens into contact with the seat therefor, substantially as described,

14. The combination with the condensersupport, of the mount or holder consisting of the case 96 having the inturned flange 97, the simple lens loosely fitting within the said case, and the lens-retainer, constituted by the spiral spring 99 fitted within the said case and engaging with the rim of the lens, the said spring pressing the lens into contact with the said inturned flange, substantially as described.

15. The condenser-support having projections 106, combined with the mount or holder ils constructed to receive and hold a condenserlens and having a ring or flange adapted to pass behind the said projections, and a notch, as 107, through which one of the said projections may pass in adjusting the mount into place, substantially as described.

16. The combination with the condensersupport, of the simple lenses constituting the component parts of the condenser-lens, and the separate mounts for said simple lenses in independently-detachable connection with the said condenser-support, at opposite sides of the latter, substantially as described.

17. The combination with the condensersupport, the condenser-lens, and a lamp, of

the lantern-hood surrounding the said lamp and separatedfrom the adjacent portion of the condenser-support by a space permitting free flow of air about the rear part of the condenser-lens, substantially as described.

18. The combination with the slide-carrier, the condenser-support, and the condensermount applied to the said condenser-support, of the plate connected with the slide-support and fitting the exterior of the said condensermount, and means to connect the said plate detachably with the condenser-support, substantially as described.

19. The combination with the slide-carrier, the condenser-support having opposite projections 113, 113, and the condenser-mount applied to the said condenser-support, of the plate connected with the slide-support and fitting the exterior of the said condensermount, the said plate having the opposite notches 114, 114, for the passage of the said projections 113, 113, and being adapted to fit behind the said projections, to secure it to the condenser-support, substantially as described.

20. The combination with the slide-carrier, of the movable piece 120 provided with means of fixing the same in the desired positions of adjustment, and the adjustable stop-screw 119 applied to the said piece, substantially as de scribed.

In testimony whereof -I affix my signature in presence of two witnesses.

JOHN A. SEAVERNS.

Witnesses:

ALICE H. MoRRIsoN, WILLIAM A. COPELAND. 

